Proportional pressure adjustment valve

ABSTRACT

A proportional pressure adjustment valve is described which comprises one valve part with inlet and outlet openings ( 4 ) and at least one closing mechanism ( 7 ) for control of a valve ( 12 ), the same as a magnet part having one magnet core, one magnet coil and one displaceably disposed magnet armature. An actuating element ( 11 ) cooperates with the armature, actuating the spherical closing mechanism ( 7 ). The hydraulically active cross section of the valve ( 12 ) is essentially determined by the length of the valve (L), the diameter of the valve (D) and th diameter (d) of the part ( 13 ) of the actuating element ( 11 ) which penetrates into the valve. According to invention, the ratio of the length of the valve (L) to the diameter of the valve (d) is less than 2.0.

FIELD OF THE INVENTION

This invention concerns a proportional pressure adjustment valvecomprising one valve part with inlet and outlet openings and at leastone closing means to control a valve on one of the openings, the same asa magnet part with a magnet core, a magnet coil and a displaceablyarranged magnet armature. Together with the armature operates anactuating element which controls the closing means, especially on thevalve on the inlet opening, the actuating element penetrating at leastpartly into the valve during the adjustment process. The hydraulicallyactive cross section of the valve is here essentially determined by thevalve length, the valve diameter and the diameter of the actuatingelement in the valve.

BACKGROUND OF THE INVENTION

One such valve is known, for example, from WO 98/48332. This valve isequipped with at least two valve steps of which two steps are coupledwith each other variably and under mechanical or hydraulic actionaccording to the principle of the hydraulic half bridge. Both variablevalve steps are provided as inlet and as outlet valves of a pressureadjustment space and each has one closing body of defined geometry.

DE 44 26 152 A1 describes an electromagnetic pressure adjustment valvewhich can be used especially for the shifting pressure adjustment ofautomatic transmission of motor vehicles. The valve has one valvehousing and one control slide actuatable by a magnet armature andconnected therewith, the slide controlling the connections from apressure medium inlet to a consumption terminal or to a reverse flowtank. The control slide is supported in a rear end and in a frontbearing point in the valve housing and is prestressed via a settingspring.

Proportional pressure adjustment valves of the above mentioned kind aresubject to a permanent further development relative to the functionalproperties, especially the optimizing of the hydraulic properties, thesame as the increase in the reliability of the operation under differingconditions.

The problem on which this invention is based is to show a proportionalpressure adjustment valve with improved hydraulic properties which, inparticular, has a flow-rate optimized valve, which has substantiallyless drags especially in the range of lower temperatures, that is, underhigh viscosities of the hydraulic fluid.

On the basis of a proportional pressure adjustment of the abovementioned kind, this problem is solved with the features stated in claim1. Advantageous developments are described in the sub-claims.

SUMMARY OF THE INVENTION

According to the invention, the proportional pressure adjustment valvehas an optimized definition of the supply geometry determinant of theflow rate, the ratio of the valve length to the valve diameter beingless than 2.0 and said flow-rate determinant valve being especiallysituated in the inlet opening of the valve. It is thus advantageouslyobtained that the inventive valve has small flow losses, especially inthe presence of high oil viscosities, that is, at low temperatures.Thereby are achieved higher flow rates and shorter response times of thevalve so that the inventive design of the proportional pressureadjustment valve advantageously makes better dynamic values possible.

In an advantageous development of the invention, it is propose that theactuating element has a pin-shaped end piece which penetrates in thevalve, it being also possible for part of the closing means to penetratein the valve instead of the actuating element. The ratio of the diameterof the actuating element in the valve to the valve diameter is less than0.9 and the diameter of the pin-shaped end piece of the actuatingelement is less than 1.0 mm. With such a design of the inlet-side valvean improved operation, especially for the pressure adjustment inautomatic transmissions of motor vehicles, is advantageously provided.

In one other design of the invention is described a flow-favoreddefinition of the edges on the inlet and outlet sides on the valve. Herethe radii and/or the chamfers of the valve and/or on the end piece ofthe actuating element corresponding to the valve are made shorter thanthe valve length itself, the radii having a value of less than or equalto 0.1 time the valve length. Thereby are likewise made possiblesubstantially lower drags of the valve geometry determinant of the flowrate.

The proportional pressure adjustment valve has a valve part with twoseat valves, one seat valve particularly containing as closing means oneball and the other seat valve being designed as flat seat. Thereby isadvantageously achieved that, with few demands on the precision of theindividual parts, the inventive valve ensures a relatively greattightness especially in its end positions whereby the leakagecharacteristics are also minimized in a flow-rate optimized valve.

In a special development of the invention, which can also represent anindependent invention, it is proposed that between both seat valves anadditional perforated valve be placed which now represents, instead ofthe inlet-side valve, the flow-rate determining cross section betweenthe inlet opening and an outlet opening. With such perforated valve,there are obtained substantially weaker drags, especially in the minustemperature range. The perforated valve described is advantageously moreexact and easier to produce than then aforementioned annular valve. Witha pressure adjuster thus optimized with regard to operation higher flowrates and shorter response times can be achieved and the dynamic valuesof the adjuster are improved. There is further ruled out the inflow dueto a possible eccentricity of the pin-shaped end of the actuatingelement in the valve.

Between the inlet-side seat valve and the perforated valve, a space aptto be made fluid-tight is provided which can be produced, for example,by an annular sealing body made of flexible material.

A hydraulic connection to the working pressure line is provided betweenthe perforated valve and the outlet opening or the seat valve on thetank side so that the working pressure line can be advantageouslydisposed in radial and axial direction in the valve body.

When implementing such a perforated valve, the external diameter of theaforementioned annular valve in the inlet opening is enlarged so thatthe flow-rate determining cross section is purposefully displaced in theperforated valve. Due to the enlargement of the external diameter of theannular valve, the minimum opening force is increased whereby an openingforce impact can occur when the annular valve opens. To dampen saidopening force impact of the inlet-side seat valve, it is proposed toprovide a spring, especially a compression spring, between the magnetcore and the magnet armature.

With an inventive proportional pressure adjustment valve, it is possibleto carry out both a shifting and an adjusting operation in adapteddesign of the magnet part. Two kinds of operation are thusadvantageously possible with one valve.

Other objectives, advantages and developments of the invention resultfrom the description that follows of the embodiments shown in moredetail in the figures. At the same time all the features andcharacteristics described and/or graphically shown are object of theinvention separately or in arbitrary, logical combinations independentlyof their summarization and references in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying drawings in which:

FIG. 1 shows in section a valve part for an inventive proportionalpressure adjustment valve with closed inlet valve;

FIG. 2 shows the valve part according to FIG. 1 with open inlet valve;

FIG. 3 shows an enlarged detail X from FIG. 2;

FIG. 4 shows in section and in reduced scale an inventive proportionalpressure adjustment valve in another design.

DETAILED DESCRIPTION OF THE INVENTION

The valve part 2 (FIG. 2) has an inlet opening 4, a tank-side outletopening 5 and a working pressure connection 6. The valve part 2 is alsoequipped with an inlet-side first seat valve 17 and an outlet-side seatvalve 18. The closing means of the first seat valve 17 is designed asball 7 which controls the inlet-side valve 12. The outlet-side seatvalve 18 is provided with a flat seat 19 which can be operated via theactuating element 11 by a magnet armature shown in FIG. 4. The actuatingelement 11 has a pin-shaped end piece 13 which operates the closingmeans 7 in the inlet-side valve 12. The actuating element 11 isdimensioned so that the two seat valves 17 and 18 are crossed with eachother according to the principle of a hydraulic half bridge. Theinlet-side seat valve 17, for example, is closed here while theoutlet-side seat valve 18 is open. In the space between the first andthe second seat valves 17 and 18 is situated a hydraulic connection 22to the working pressure line 6.

In the opposite end position (FIG. 2), the inlet-side seat valve 17 isfully open while the outlet-side seat valve 18 is closed. (In thefigures the same parts have been identified with the same number). Thepin-shaped end piece 13 of the actuating element 11 penetrates the valve12 and lifts the spherical closing element 7 from its annular sealingsurface. The pressure medium flowing in through the inlet opening 4reaches through the valve 12 a space between both valve seats 17 and 18.The pressure medium is here deflected and led through the hydraulicconnection 22 to the working pressure line 6.

The inlet-side valve 12 (FIG. 3) has on its inlet side a radius 14 andalso a chamfer 16 on its outlet side. The front side of the pin-shapedend piece 13 of the actuating element 11 is likewise provided with aradius 15. In an advantageous embodiment of a proportional pressureadjustment valve for use as shift valve in an automatic transmission ofa motor vehicle, the diameter of the ball 7 amounts to 1.588 mm whilethe diameter of the corresponding valve 12 amounts to 1.20 mm. Thediameter d of the pin-shaped end piece 13 amounts to 0.60 mm and thevalve length L to 0.50 mm. The inlet-side radius 14 of the valve 12amounts to 0.05, the radius 15 on the end piece 13 amounts to 0.02 mmand the chamfer 16 is designed with 0.20 time 45°.

In an alternative design (FIG. 4) is shown a proportional pressureadjustment valve 1 comprised of a valve part 2 and a magnet part 3. Themagnet part 3 essentially consists of one magnet core 8, one magnet coil9 and one displaceably, disposed magnet armature 10 which interacts withthe actuating element 11. Between the magnet core 8 and the armature 19,a compression spring 23 is provided for damping a force impact duringopening of the inlet-side seat valve. The magnet part 3 can be attachedvia an electric feed line 24.

The basic construction of the valve part 2 is similar to the abovedescribed parts but has an inlet opening 4 in communication with apressure line P, the same as an outlet opening 5 in communication with atank T and a terminal 6 in communication with a working pressure line A.Between the inlet-side seat valve 17 and the outlet-side valve 18, aperforated valve is provided. In order that the perforated valve 20forms the cross section of the valve part that determines the flow rate,the hole of the annular valve 12, compared with the valve shown in FIGS.1 to 3, is slightly enlarged, for example, from about 0.30 mm to 0.50 mmin the outer diameter D. Such a perforated valve is more exact andeasier to produce than the above described annular valves. Between theseat valve 17 and the perforated valve 20, the space 21 is delimited byan annular body 25 so that the pressure medium first has to flow throughthe perforated valve 20 in order to arrive at the hydraulic connection22 to the working pressure line 6. To dampen an opening force impactpossibly occurring due to the enlarged surface of the valve 20, acompression spring 23 is placed between the magnet core 8 and the magnetarmature 10.

In the end position, shown in FIG. 4, the inlet-side annular valve 12 isclosed while the outlet-side seat valve 18 is open. In an inverse endposition, not shown, of both seat valves the ball 7 is lifted from theseat of the valve 12 and the seat valve 18 is closed. The pressuremedium thus arrives through the inlet opening 4 and via the annularvalve 12 at the intermediate space 21. Thereafter the pressure mediumflows through the perforated valve 20 determinant of the flow rate andthe hydraulic connection 22 to the working pressure terminal 6.

Reference numerals 1 proportional pressure adjustment 17 seat valvevalve 18 seat valve 2 valve part 19 flat seat 3 magnet part 20perforated valve 4 inlet opening 21 space 5 outlet opening 22 hydraulicconnection 6 working pressure line/connection 23 compression spring 7closing means (ball) 24 electric inlet 8 magnet core 25 annular body 9magnet coil 10 magnet armature P pressure line 11 actuating element Ttank 12 annular valve A working pressure line 13 end piece (pin) Xdetail 14 radius d pin diameter 15 radius D valve diameter 16 chamfer Lvalve length

1. A proportional pressure adjustment valve (1) comprising: a valve part(2) with inlet and outlet openings (4, 5, 6) and at least one closingmechanism (7) for control of a valve (12) interacting with one of saidinlet and outlet openings, a magnet part (3) with a magnet core (8), amagnet coil (9) and a displaceably disposed magnet armature (10); and anactuating element (11) which interacts with said armature (10) forcontrolling operation of the closing mechanism (7); wherein ahydraulically active cross-section of said valve (12) is determined by avalve length (L), a valve diameter (D) and a diameter (d) of apin-shaped end piece (13) of said actuating element (11) that penetratesinto said valve; and a ratio of said valve length (L) to said valvediameter (D) is less than 2.0.
 2. The proportional pressure adjustmentvalve according to claim 1, wherein the ratio of said diameter (d) ofthe pin-shaped end piece (13) of said actuating element (11) in saidvalve (12) to the valve diameter (D) is less than 0.9 and the diameter(d) is less than 1.0 mm.
 3. The proportional pressure adjustment valveaccording to claim 1, further comprising at least one of a first edgeradius, chamfer radius formed on said valve (12) and a second edgeradius formed on said pin-shaped end piece (13) of said actuatingelement (11) corresponding with said valve (12) and wherein at least thefirst and second edge radii are smaller than the valve length (L),having a value below or equal to 0.1 times the valve length (L).
 4. Theproportional pressure adjustment valve according to claim 1, wherein thevalve (12) is a first valve and said valve part (2) has first and secondvalves, the first valve (12) has a ball (7) as the closing mechanism (7)and the second valve (18) having a flat seat (19).
 5. The proportionalpressure adjustment valve according to claim 1, wherein the proportionalpressure adjustment valve provides both a shifting and an adjustmentoperation.
 6. A proportional pressure adjustment valve (1) comprising: avalve part (2) with inlet and outlet openings (4, 5, 6) and at least oneclosing means (7) for control of a valve (12) associated with one ofsaid openings, a magnet part (3) with a magnet core (8), a magnet coil(9) and a displaceably disposed magnet armature (10); and an actuatingelement (11) which interacts with said armature (10) to actuate saidclosing means (7), wherein a hydraulically active cross-section of saidvalve (12) is determined by a valve length (L), a valve diameter (D) anda diameter (d) of a part of said actuating element (11) that penetratesinto said valve, and a ratio of said valve length (L) to said valvediameter (D) is less than 2.0; the valve (12) is a first valve and thevalve part (2) has the first valve and a second valve, the first valve(12) has a ball (7) as the closing means, and the second valve (18) hasa flat seat (19), and between said first and second valves (12, 18) is aperforated shutter (20) having a cross-section determinant of the flowrate between said inlet opening (4) and an outlet opening (5),particularly of a working pressure line (6).
 7. The proportionalpressure adjustment valve according to claim 6, wherein the first valve(12) is located between said inlet opening (4) and said perforatedshutter (20) and a hydraulically sealable space (21) is provided betweenthe first valve (12) and the perforated shutter (20).
 8. Theproportional pressure adjustment valve according to claim 6, wherein ahydraulic connection (22) to said working pressure line (6) is providedbetween said perforated shutter (20) and said second valve (18).
 9. Theproportional pressure adjustment valve according to claim 6, wherein aspring is provided, between said magnet core (8) and said magnetarmature (10), to dampen any force impact during opening of the firstvalve (12).
 10. A proportional pressure adjustment valve (1) comprising:a valve part (2) with inlet and outlet openings (4, 5, 6) and at leastone closing mechanism (7) for control of a valve (12) interacting withone of said inlet and outlet openings, a magnet part (3) with a magnetcore (8), a magnet coil (9) and a displaceably disposed magnet armature(10); and an actuating element (11), operably coupled to open theclosing mechanism (7), which interacts with said armature (10) forcontrolling operation of the closing mechanism (7); a hydraulicallyactive passage of said valve (12) having a valve length (L), a valvediameter (D) and a diameter (d) of a pin-shaped end piece (13) of saidactuating element (11) that penetrates into said valve, and wherein saidvalve length (L) is less than one-half (0.5) said valve diameter (D),and said diameter (d) of the pin shaped end piece (13) is greater thanthe valve length (L) of the valve.
 11. The proportional pressureadjustment valve according to claim 10, wherein said diameter (d) of thepin-shaped end piece (13) of said actuating element (11) is less than1.0 mm.
 12. The proportional pressure adjustment valve according toclaim 10, wherein at least one of a first edge radii (14), a chamfer(16) on said valve (12) and a second radii (15) on said pin shaped endpiece (13) of said actuating element (11) corresponding with said valve(12), are smaller than the valve length (L), and at least the first andsecond radii having a value below or equal to 0.1 times the valve length(L).
 13. The proportional pressure adjustment valve according to claim10, wherein the valve (12) is a first valve and the valve part (2) hasfirst and second valves, the first valve (12) has a ball (7) as theclosing mechanism (7) and the second valve (18) having a flat seat (19).